US Patent 8109099 Flow sleeve with tabbed direct combustion liner cooling air

A combustion duct for a gas turbine engine has a combustion liner to receive products of combustion, and deliver the products of combustion downstream toward a turbine rotor. An outer housing is positioned radially outwardly of the combustion liner. A flow sleeve is positioned radially intermediate the outer housing and the combustion liner. A chamber radially outwardly of the flow sleeve receives cooling air. A plurality of holes through the flow sleeve deliver cooling air from the chamber against an outer periphery of the combustion liner. A plurality of tabs are associated with at least some of the holes in the flow sleeve. The tabs are positioned to extend radially inwardly on a downstream side of the holes.